How atoms are displayed in OpenGL
Atoms colors and radii are defined in the files ATOM_COLORS.DEF and ATOM_RADIUS.DEF respectively. A site defined as:
site S1 occ Al+3 1 beq 1
will be displayed as a Sulfur atom. If the Site Name, minus the numbers, is not found in ATOM_COLOURS.DEF then the atom type defined at the first site occupancy is used. Thus a site defined as:
site _S1 occ Al+3 1 beq 1
will be displayed as an Aluminium atom.
— Alan Coelho 2017/07/19 12:25
On an old laptop the structure viewer in the test version of topas v7 wouldn't work. The graphics card (intel integrated graphics 3000) didn't support opengl, though topas v6 worked fine. If you get this problem you can try the work around at https://gist.github.com/rb-dahlb/26f316c5b6089807a139fc44ee69f0d1. It slows the viewer down significantly, but prevents the crash.